King Charles has been urged to cancel his upcoming trip to the US amid threats of “humiliation” from activists. The King and Queen are reportedly planning to mark the 250th anniversary of US independence by visiting President Donald Trump in April, but campaigners have warned that they would be met with an “attack” campaign from American dissidents. Political strategist Steve Schmidt, co-founder of pro-democracy group the Save America Movement, said the monarch would be met with a “humiliating, no holds barred” onslaught after touching down stateside.

Mr Schmidt said US citizens would take issue with the implicit “celebration” of Mr Trump’s unpopular regime signalled by the trip and could mimic the campaign launched by UK activists during the President’s state visit last year, when images of him with Jeffrey Epstein were projected onto various buildings. “I will project images onto buildings in New York City,” he told the Daily Beast podcast. “I will run ad campaigns that … boggle the British imagination.”

“Should the King come to Washington, it will be a celebration of Donald Trump in a moment of existential crisis for American democracy,” Mr Schmidt continued.

“Should he set foot on American soil in service of MAGA as a propaganda tool, then the crown will be attacked with an advertising campaign that would not be permitted in England. It will be no holds barred. It will be mortifying for the entire British government.”

The Save America Movement has previously run ads in Denmark opposing Mr Trump’s bid to seize Greenland and plans to spend up to $100 million (£73 million) in the run-up to the November mid-terms.

Although Buckingham Palace has yet to officially announce this year’s US state visit, the monarch’s plans to mark the milestone anniversary months after hosting Mr Trump on a lavish UK trip have been widely reported.

The US President’s affinity for the Royal Family was on full display as he was treated to a state banquet and 41-gun salute and described King Charles as an “elegant gentleman” and a “friend” last September.

Royal expert Jennie Bond suggested the King was “the perfect person” to bridge the divide between Mr Trump and other Western powers amid division caused by his increasingly erratic behaviour.

“Because the President is so enamoured with British royalty and so hopelessly flattered by any attention he’s given by the royal family, they have become key players in the so-called special relationship,” she told The Mirror last month.

“But you have to remember that the King acts on the wishes of the Government. So the decision about any state visit to America is entirely dependent on what the Prime Minister and his Government want.”